Title of Thesis

Effect Of Mixed Industrial Wastewater On Soil, Tree Biomass Production And Trace Metal Uptake

Author(s)

Syed Fazal ur Rehman Shah

Abstract
Although the agricultural use of wastewater raises some environmental and human health concerns, irrigation with wastewater is usually carried out by smallholders in dry areas. The present study reports on the physiological effect of several dilutions of the raw wastewater of the Hudiara drain on Dalbergia sissoo and Eucalyptus camaldulensis plants. Six-month old seedlings were established in pots and irrigated for 18 months with: tap water (control, T0); 25% wastewater (T1); 50% wastewater (T2); 75% wastewater (T3); and 100% wastewater (T4). Results showed that the plant growth parameters decreased as the percent of wastewater increased. At T4 the shoot length, number of leaves, leaf fresh weight, and leaf oven dry weight were reduced by 17%, 72%, 72%, and 70% in Dalbergia sisoo and 5%, 17%, 23%, and 29% in Eucalyptus camaldulensis plants respectively, compared to the control (T0).
The content of chlorophyll a, chlorophyll b and total chlorophyll increased in Dalbergia sissoo plants treated with wastewater at 25%, but decreased in the T2, T3, and T4 treatments. Whereas chlorophyll a, chlorophyll b and total chlorophyll increased up to T2 in E. camaldulensis, in treated pots beyond that percentage, a decline in chlorophyll was observed.
As the percentage of wastewater in the treatments increased, the accumulation of Na, Cd and Cr in tissues increased, while the concentration of K, P, Mg, and Fe decreased. Similarly, Eucalyptus camaldulensis and Dalbergia sissoo plants were irrigated with synthetic wastewater containing Cd and Cr for 18 months. Treatments were T0= Tap water (control); T1= 0.05+1.0 mg L-1conc. of Cd(II)+ Cr(VI); T2= 0.10+2.0 mg L-1conc. of Cd(II)+ Cr(VI); T3= 0.20+4.0 mg L-1conc. of Cd(II)+ Cr(VI) and T4= 0.40+8.0 mg L-1conc. of Cd(II)+ Cr(VI). Results showed that plants at T1 grew more compared to the control, but beyond that level, a gradual decline in growth was recorded with a maximum reduction in T4 treated plants. Cd and Cr accumulation in tissues increased (roots>shoot>leaves) as external metal concentration increased, while nutrient accumulation (K, P, Mg, Fe) and chlorophyll content declined. However, the application of synthetic wastewater containing various concentrations (0, 10, 20, 40 and 80 mg L-1) of Cd and Cr on the growth of Dalbergia sissoo at the seedling stage for four weeks under controlled conditions in a growth chamber (300 μmol m-2s-1 of photosynthetically active radiation with 16:8 hours photoperiod) revealed a decline in growth after 10 mg L-1 and 40 mg L-1 for Cr and Cd, respectively. A combined application of Cd and Cr wastewater showed a growth reduction at doses above 20 mg L-1. Results showed that Cr was more toxic to Dalbergia sissoo plants at the seedling stage than Cd. The present study suggests that wastewater from the Hudiara drain diluted to 25% and 50% with tap water is a feasible option for the growth of D. sissoo and E. camaldulensis plants in Lahore, Pakistan.
A phytosociological survey using the Braun-Blanquet’s approach was undertaken to investigate the influence of the Hudiara drain wastewater on the surrounding vegetation. Multivariate analysis of vegetation data classified the vegetation into two major communities including, Cynodon dactylon and Boerhaavia diffusa, and Parthenium hysterphorus and Xanthium strumarium groups. The fervent growth of these species designated the area as wasteland. The patterns of floral diversity exhibited considerable variation. Canonical Correspondence Analysis (CCA) revealed that the distribution of vegetation correlates with environmental variables, but their role in the grouping of species was not significant. However, soil EC played a role in the grouping of Stellaria media and Fagonia cretic.Similarly, some species, namely Riccinus communis, Boerhaavia diffusa and Phragmites karka showed a correlation with Fe and Cr respectively, suggesting Phragmites karka as a suitable candidate for chromium contaminated sites.

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1.1 Background
1.2 Historical Purspective of Phytoremediation
1.3 Site Description
1.4 Objectives of the Study
1.5 Thesis Layout

2.1 Origin and Occurrence
2.2 Effects of Heavy Metals on Human Health
2.3 Effect of Wastewater Application on Soil Properties
2.4 Heavy Metal Toxicity in Plants
2.5 Effect of Heavy Metals on Growth and Development
2.6 Effect of Heavy Metals on Plant Physiology
2.7 Effect of Heavy Metals on Enzymatic System
2.8 Effect of Wastewater Application to Plantations

3.1 Wastewater Sampling and Analysis
3.2 Soil Analysis
3.3 Procurement and Raising of Seedlings
3.4 The Hudiara drain Wastewater Application
3.5 Synthetic Wastewater Application
3.6 Plant Growth Analysis
3.7 Plant Digestion and Analysis
3.8 Chlorophyll Determination
3.9 Analytical Quality Assurance
3.10 Experimentation under Controlled Conditions
3.11 Phytosociological Survey
3.12 Statistical Analysis

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4.1 The Influence of Heavy Metals on Dalbergia sissoo Seedlings under Controlled Water and Climate Conditions
4.2 Effects of the Hudiara drain Wastewater on Growth and Biomass Broduction of Eucalyptus camaldulensis and Dalbergia sissoo Plants
4.3 Effect of Synthetic Wastewater on Growth and Biomass Production of Tree Species

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5.1 Vegetation Profile of the Hudiara Drain
5.2 Classification of Vegetation
5.3 Vegetation and Environmental Variables

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6.1 Conclusions
6.2 Suggestions for Future Work

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